Stochastic resonance (SR), a counterintuitive phenomenon in which slight amounts of environmental noise actually increase the discernability of signals or stimuli, produces a demonstrable effect in human sensory cells. In both healthy young and clinical subjects- elderly, diabetics, and stroke sufferers-a significant increase in tactile and proprioceptive sensitivity is noted when electrical or mechanical noise is presented at the site of the stimulus. Dysfunction in these sensory systems is known to have significant clinical sequellae including gait abnormalities, propensity to fall, and foot ulcers. Together, these conditions cost the U.S. healthcare system many billions of dollars annually. The goal of the proposed researches to advance early laboratory results toward a therapeutic device for enhancing the tactile and proprioceptive sensitivity of patients in these large clinical populations. The work will focus on use of mechanical noise to produce the desired beneficial effect. Two significant limitations in current understanding will be addressed. First, we will determine the characteristics of mechanical noise that produce the optimal sensory enhancement. This information is key to the design of prototype actuators and products. Second, in tests representative of activities of daily living we will explore whether use of mechanical noise provides a true functional benefit. PROPOSED COMMERCIAL APPLICATIONS: If successful, the proposed research will lead to medical devices that improve tactile and proprioceptive sensitivity in people who suffer from peripheral numbness. This would improve quality of life for these individuals while reducing the costs of caring for them. Additional medical applications include uses in upper extremities, some forms of incontinence, and rehabilitation medicine.